The present invention relates to an elevator shaft closure, which is preferably used for elevator installations with fire protection requirements as are demanded in known standards.
The elevator shaft closure enables access from the floor to the car. It includes the principal parts of a door frame and at least one door leaf. The door frame, typically including a header and/or ceiling plate, is alternatively connected, depending on the type of building, directly with a wall or on a foundation frame. At least one door leaf is slidably mounted in the door frame. Depending on the possible forms of arrangement of the door leaves, distinction is then made between single-leaf or multi-leaf telescopic doors or center doors. Telescopic doors close and open on one side, whereas center-opening doors close from both sides towards the center or middle of the door opening (and open from the middle of the door opening toward both sides). Each door is actuated by exertion of a force onto the door, and the door moves via one or more rollers attached to the door interacting with a rail.
The fire safety of elevator landing door systems during fires in buildings is ensured by a standard fire test of door assemblies regulated by the requirements defined in an applicable country standard. For example, under the UL 10B standard in the United States, the temperature in a test heating furnace gradually ramps from ambient to 982° C. during 90 minutes to simulate possible fire conditions in an actual building. One of the primary requirements for successfully passing the test is absence of visible flames in any component of the door assembly for the whole duration of the test. For example, in a typical test furnace the temperature is controlled by a specified time-temperature curve; any flaming on the unexposed door surface is recorded. The test typically requires that no flame should be observed on the unexposed door surface during the first 30 minutes, and no flame should last more than five (5) seconds after thirty minutes during testing.
In light of the foregoing, the present invention aims to resolve one or more of the aforementioned issues that afflict elevator systems, particularly door assemblies.